<?php
    header('Content-type:text/html;charset=utf-8');
    $name = '小明';
    $score= 78;
    if(is_int($score)  ||   is_float($score)){
         if($score >=90 && $score <=100){
               $str ='A级';
        }elseif($score >=80 &&  $score <90){
             $str ='B级';
           }if($score >=70 && $score <=80){
             $str ='C级';
          }elseif($score >=60 &&  $score <70){
             $str ='D级';
         }elseif($score >=0 && $score <60){
             $str ='E级';
     }else{
                $str = '学生成绩范围必须在0～100！';
 	  }
 	}else{
 	$str= '输入的学生成绩不是数值!';
 	                 }
 	  echo "<h2>学生成绩等级</h2><p>学生姓名：".$name."<p>学生分数：".$score."分<p>成绩等级：".$str;